Composite cartridge case

ABSTRACT

A cartridge case has a heel element having a forward portion, a generally flat rear end portion, and a circumferential groove, having a generally radially extending rear face and a sloped forward face. A separate generally tubular sidewall, extends over the forward portion of the heel element and over the sloped forward face into the circumferential groove.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent Application Ser. No. 61/891,127 filed Oct. 15, 2013. The entire disclosure of the above application is incorporated herein by reference.

FIELD

The present disclosure relates to ammunition and in particular to a composite cartridge case for ammunition.

BACKGROUND

This section provides background information related to the present disclosure which is not necessarily prior art.

Cartridge cases have traditionally be made of brass because brass is relatively easy to form, and has adequate properties (e.g., strength) to withstand the firing of the cartridge. However, brass is a relatively expensive metal, which affects the cost of ammunition. Brass is also a relatively heavy metal, increasing the weight of ammunition, which limits the amount of ammunition that can be carried or transported.

SUMMARY

This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.

Embodiments of the present invention provide a cartridge case, and ammunition with a cartridge case that can be made with lower cost, lighter weight materials than conventional brass cartridge cases and cartridges. Generally a cartridge case in accordance with the preferred embodiment of this invention comprises a heel element having a forward portion, a generally flat rear end portion, and a circumferential groove, having a generally radially extending rear face and a sloped forward face. A separate generally tubular sidewall extends over the forward portion of the heel element and over the sloped forward face into the circumferential groove. The circumferential groove in the heel portion preferably has a bottom face, facing generally radially outwardly, disposed between the forward face and the rearward face, and wherein the rearward end portion of the tubular sidewall extends over the sloped forward face and at least part of the bottom face.

The forward portion of the heel element is preferably generally cup-shaped, comprising a wall that tapers toward its forward end. Similarly the circumference of the wall preferably also tapers toward the forward end of the heel element. The tubular sidewall is preferably widest at the junction between the front face of the circumferential groove and the wall of the cup-shaped portion, tapering toward its forward end and toward its rearward end.

The heel portion can be made from a first metal or metal alloy, such as stainless steel, and the tubular sidewall can be made from a second metal or metal alloy, such as aluminum or an aluminum alloy.

A bonding agent can be provided between the generally tubular sidewall and the heel portion, if desired.

The cartridge case is preferably assembled into a cartridge comprising a primer disposed in an opening in the heel element, a bullet or other projectile seated in the forward end of the tubular sidewall, which can neck down as is known to accommodate a bullet or projectile that is smaller than the tubular sidewall. A propellant is disposed inside the cartridge.

Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

FIG. 1 is a longitudinal cross-sectional view of a preferred embodiment of a cartridge case constructed according to the principles of this invention;

FIG. 2 is a longitudinal cross-sectional view of a cartridge assembled from a preferred embodiment of a cartridge case constructed according to the principles of this invention;

FIG. 3A is a longitudinal cross sectional view of a heel element prior to completion;

FIG. 3B is a longitudinal cross sectional view of a heel element after completion;

FIG. 3C is a longitudinal cross sectional view of the tubular side wall prior to installation over the heel element;

FIG. 3D is a longitudinal cross sectional view of the tubular side wall after installation over the heel element;

FIG. 3E is a longitudinal cross sectional view of the tubular side wall after being engaged to the heel element; and

FIG. 3F is a side elevation view of the completed cartridge case.

Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.

DETAILED DESCRIPTION

Example embodiments will now be described more fully with reference to the accompanying drawings.

Embodiments of the present invention provide a cartridge case, and ammunition with a cartridge case that can be made less expensively and of lighter weight than conventional brass cartridge cases and cartridges. A cartridge case in accordance with the preferred embodiment of this invention is indicated generally as 20 in FIG. 1. The case 20 comprises a heel element 22 having a forward portion 24, a generally flat rear end portion 26, and a circumferential groove 28, having a generally radially extending rear face 30 and a sloped forward face 32. A separate generally tubular sidewall 24 extends over the forward portion 24 of the heel element 22 and over the sloped forward face 32 into the circumferential groove 28. The circumferential groove 28 in the heel portion 22 preferably has a bottom face 38, facing generally radially outwardly, disposed between the forward face 32 and the rearward face 30. The rearward end portion 40 of the tubular sidewall 34 extends over the over the sloped forward face 32 and at least part of the bottom face 38.

The forward portion 24 of the heel element 22 is preferably generally cup-shaped, comprising a wall 42 that tapers toward its forward end 44. Similarly the circumference of the wall 42 preferably also tapers toward the forward end of the heel element. The tubular sidewall 34 is preferably widest at the junction 46 between the front face 32 of the circumferential groove 28 and the wall 42 of the cup-shaped portion, tapering toward its forward end and toward its rearward end.

The heel element 22 can be made from a first metal or metal alloy and the tubular sidewall 34 can be made from a second metal or metal alloy. In this preferred embodiment, the heel element 22 can be made of stainless steel, which is strong, relatively inexpensive, and corrosion resistant. The sidewall can be made of aluminum or an aluminum alloy, which is light weight and relatively easy to form.

A bonding agent can be provided between the generally tubular sidewall and the heel portion, if desired. Whether such an agent is desirable depends upon the particular cartridge, the thickness of the tubular sidewall, and the type and amount of propellant.

As shown in FIG. 2, the cartridge case 20 is preferably assembled into a cartridge 100 comprising a primer 48 disposed in an opening 48 in the heel element, a bullet or other projectile 52 seated in the forward end 54 of the tubular sidewall 34, which can neck down at 56 as is known to accommodate a bullet or projectile that is smaller than the tubular sidewall. A propellant is disposed inside the cartridge.

A method of manufacturing the cartridge case 20, and thus a cartridge 100 made from the cartridge case 20, is illustrated in FIG. 3. As shown in FIG. 3A a proto heel element 22 is made, for example by machining, stamping or preferably impact extrusion. The proto heel element 22′ has the forward portion 24 comprising the wall 42 tapering toward its forward end 44. The proto heel element 22′ also has a generally flat rear end 26, with an opening 50 for receiving a primer.

As shown in FIG. 3B, the proto heel element 22′ is further processed to form the circumferential groove 28, with the sloped front face 32, the flat rear face 30, and preferably a flat bottom 38. The outside circumference of the wall 42 is also made to taper toward the forward end 44.

As shown in FIG. 3C, the tubular sidewall 34 is formed, for example from a tube of aluminum.

As shown in FIG. 3D, the rear end portion 40 of the tubular sidewall is fit over the forward portion 24 of the heel element 22. Adhesives or other bonding agents may be disposed on the outside of the heel element 22 or the inside of the tubular sidewall 34 to facilitate bonding between the heel element and the tubular sidewall.

As shown in FIG. 3E, the rear portion 40 of the sidewall is pressed into the circumferential groove 28, with a portion of the sidewall overlying the sloped front face 32, and preferably a portion also overlying the bottom 38. The forward end of the sidewall 34 can also be shaped as needed

The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure. 

What is claimed is:
 1. A cartridge case comprising: a heel element having a forward portion, a generally flat rear end portion, and a circumferential groove, having a generally radially extending rear face and a sloped forward face; a separate generally tubular sidewall, the rearward end portion of the sidewall extending over the forward portion of the heel element and over the sloped forward face into the circumferential groove.
 2. The cartridge case according to claim 1 wherein the forward portion of the heel element is generally cup-shaped, comprising a wall that tapers toward its forward end.
 3. The cartridge case according to claim 2 wherein the circumference of the wall tapers toward the forward end of the heel element.
 4. The cartridge case according to claim 1 wherein the heel portion is made from a first metal or metal alloy and the tubular sidewall is made from a second metal or metal alloy.
 5. The cartridge case according to claim 4 wherein the heel portion is made from stainless steel.
 6. The cartridge case according to claim 5 wherein the tubular sidewall is made from aluminum or an aluminum alloy.
 7. The cartridge case according to claim 3 wherein the tubular sidewall is widest at the junction between the front face of the circumferential groove and the wall of the cup-shaped portion, tapering toward its forward end and toward its rearward end.
 8. The cartridge case according to claim 1 further comprising a bonding agent between the generally tubular sidewall and the heel portion.
 9. The cartridge case according to claim 1 wherein the circumferential groove has a bottom face, facing generally radially outwardly, disposed between the forward face and the rearward face, and wherein the rearward end portion of the tubular sidewall extends over the sloped forward face and at least part of the bottom face.
 10. A cartridge case comprising: a heel element, made of a first material, having a forward portion, a generally flat rear end portion, and a circumferential groove, having a generally radially extending rear face and a sloped forward face; a separate generally tubular sidewall, made of a second material, different from the first material, the rearward end portion of the sidewall extending over the forward portion of the heel element and over the sloped forward face into the circumferential groove.
 11. The cartridge case according to claim 10 wherein the forward portion of the heel element is generally cup-shaped, comprising a wall that tapers toward its forward end.
 12. The cartridge case according to claim 12 wherein the circumference of the wall tapers toward the forward end of the heel element.
 13. The cartridge case according to claim 13 wherein the heel portion is made from stainless steel.
 14. The cartridge case according to claim 14 wherein the tubular sidewall is made from aluminum or an aluminum alloy.
 15. The cartridge case according to claim 13 wherein the tubular sidewall is widest at the junction between the front face of the circumferential groove and the wall of the cup-shaped portion, tapering toward its forward end and toward its rearward end.
 16. The cartridge case according to claim 10 wherein the circumferential groove has a bottom face, facing generally radially outwardly, disposed between the forward face and the rearward face, and wherein the rearward end portion of the tubular sidewall extends over the over the sloped forward face and at least part of the bottom face.
 17. The cartridge case according to claim 17 further comprising a bonding agent between the generally tubular sidewall and the heel portion. 